Sliding contact electric switches



P 1959 J. CLAVEL 2,904,647

SLIDING CONTACT ELECTRIC SWITCHES Filed Aug. 26, 1955 2 Sheets-Sheet 1 IN VEN TOR Ea); (/EVE ATTORN YS Sept. 15", 1959 J. CLAVEL I I 2,904,647

smnmc CONTACT ELECTRIC SWITCHES 4 Filed Aug. 26, 1955 2 Sheets-Sheet 2 I mvzm-on jean ('lave/ ATTOR NEYS United ,StatesPatent 2,904,647 SLIDING coarser sworn-to swrrcnrs Jean Clavel Nanterre, France Application August as, 1953, semi Nb. seams Claims priority; application France August 31, 1954 is cums, (Cl. zoo-m The "present 'invention'ihas *for its object to improve sliding contact electric selector switches so as to produce improved electrical contact, with a simpler construction and at lower cost compared with switches hitherto available;

According to one embodiment the moving contact device is rigid and-canmove in adirection at: approximately right angles to the plane of the fixed contact surfiaces, the moving contact being pressed against said fixed con tacts by a flexible member to which itisconnected' imam orientabl'e' manner.-

The flexible member preferably acts on a-point of the moving contact-located on the axis perpendicular to the contact area and passing through the center thereof.-

Due to that disposition, the construction :of the change over switch is relatively simple, and much simpler than the construction of laminated brushes wherein each lamination must beformedand dimensioned in a particular manner. Besides,- its construction does not necessitate precision work since evenlarge tolerances are allowed; the moving contactareais permanently and completely applied on the fixed contactareast The contact pressure is -not limited by the risk of a permanent deformation ofthe flexible parts since they are independent and can be dimensioned in consequence, and the heating of the contacts has practically noinfllr ence on that pressure. Lastly, the moving contact may bemade, entirely or in part, of a particularly suitable material such as silver or a sintered alloy,- a

The resilient member may, for instance be made of a flat sprin'g strip parallel to the plane of; the contact areas, the ends thereof being fixed to a rigid support. Such a strip can be deformed by the action of the force of Contact, which is perpendicular to said plane, but not by that ofthe force' applied to the control membenl'or securing the connection or the disconnection, which is parallel to thatgplane.

For ensuring the orientation of the moving contact with reference to the resilient member, said' moving contact may comprise a member having a cylindrical cavity in which is located a spherical member secured to the resilient member and touching the bottom of said cavity. a 7

There is provided, preferably; a certain play between the said spherical memberand the sidewalls of the cylin drical cavity of the moving 'contact, so that no mechanical rigid connection exists between the moving contact anditscentrolli-ng devie n p The above described details are particularly applicable to sliding contact electncselector switches ice. to switches in which the-elementary circuits are connected to ems- 1 elementary track comprising a plurality of studs, while the commutation channels are connected to a directing track which is alsofixed, eachindividual stud being? selectively connectable; to the directing track by a movable conducting member hereaiter referred to as the bridging selector member which slides into contact with the two tracks.

The bridging selector member may comprise two mow ing' contact member's disposed as referred to ab'ovcand connected together, for instance, by a flexible conductor According to another improvement, the fixed contact studs of the elementary track mutually imbricated but electrically insulated from one another.

Inthe application of the invention to high-intensity current selector switches, the elementary track on the one hand and the directing trackon the-other hand man! be disposed in two difierent planes between which the movable contact devices are moved.

The elementary track and the directing trackare set,- preferably, in this case, opposite one another in two parallel planes between which the bridging selectormemher is move'd b-y means'of a control member.

Each moving contact may, for instance, be carried by a flexible bar, the two bars being connected together by connecting devices passing through the moving control member, preferably with a certain play.

The embodiments referred to in the preceding three paragraphs offer the additional advantage over the embodiments previously referredto that, for each bridging selector member, the contact pressure is equally distributed to both contact sections on the elementary track on the one hand-,- and on the directing track onthe other hand, and also that that pressure does not depend on any of the other members composing the apparatus (for instance members ofother bridging selector members ifi there are several of them and members composing con trol devices; driving devices, positioning, assemblin-grand fixing means) ,and does notact upon them.

In order that the ginvention may be more clearly understood, rcference will now be made to the accompanying drawings,- which show certain embodiments thereofby way of example, and in which: a

Fig. 1 represents a perspective view of a portion of a selector switch according to the invention,

Figs 2 asectional view of adetail of same.-

Fig. 3 a side elevation corresponding to Fig, l.

Fig. 4 a front elevation of same.

Fig. 5 a plan view of a variant of fixed studs;

Figs 6 is a sectional view along VI- VI of Fig. 8 showing a further embodiment and Fig. 7 a half section along VH-VII of Fig. 6.

Fig 8 a section along VI II-VIII of Fig. 6.

In the drawings, like reference numerals refer to like parts.

Iinthe embodiment shown in Figs. 1 to 4, the selector switch comprises an elementary track comprisinga-plurality of fixedstuds :11), which can be connected by a bridgiing selector member to a fixed directing track, and are distributed in an arcuate path on arigid plate 2'.- For the sake of simplicity the drawing represents a part only of the elementary track comprising a series of studs, and only the part of the bridging selector member cooperating with that series of studs. The directing part is not shown,- but is conventional and forms no part per se of the present invention.

7 The bridging selector member comprises two cylindrical moving contacts 3, each one of which is connected to a fiat spring blade 4 which is parallel to the plane 'of the contact areas of the studs 1b, and has its endsfixed, thropgh supporting legs 5, to a control member or yoke This latter is fixed on a control road 7 which passes through plate 2 concentrically to the studs 15 and can revolve around its axis but not move longitmiinnlly.

\ The connection between contact 3 and the blade ttis insured by a ball 8 (Fig. 2) which is housed in a cylindrical cavity 9 of the contact body, slightlyllarger" in diameter than the ball and which carries a bolt 10' riveted to the blade,'4.-

Around each contact body 3 is fitted a clip 11, and

the two clips are connected by a flexible electrical conductor 12.

In operation, the movement communicated to the moving yoke 6 by the control member is transmitted to the moving contacts 3 through the intermediary of the blades 4 and of the balls 8, the equatorial line of which touches the wall of the corresponding cylindrical cavity. The surfaces of contact of the moving elements 3, therefore, are caused to move in the plane of the contact areas of the studs 1b and slidingly to cover those contact areas.

The contact pressure results from the deformation of the blades 4, and it is transmitted to the contacts 3 through the balls 8 touching a point at the bottom of the cavities 9.

As the moving contacts 3 can swivel around the balls and take any position imposed upon them, the areas of the moving contacts are strongly applied, under the action of the contact pressure, on the contact areas of the tracks, even if the latter are not exactly level with the fixed plane of contact.

Consequently, the effective area of contact is'maximum and constant and the pressure is distributed uniformly at all points of that contact area.

The studs 1b of the elementary track may have, instead of a circular section as in Figs. 1 to 4, such a section that they are imbricated or overlapped as shown in Fig. 5; in which case the moving contacts 3 have a diameter not exceeding the width of the central part of the stud, as shown in dotted lines in Figure 5. Due

to this disposition, the displacement needed for the switching allows the effective area of contact between the fixed and moving contacts to remain practically constant, and the moving contacts have no tendency to rock when passing from one stud to another.

In the embodiment shown in Figures 6 to 8, the selector switch comprises two supports 2a and 2b united by cross members 28 and on which the directing track In and the elementary track comprising studs 1b are disposed in an arcuate path.

The moving support 6 is fixed to a shaft 7 pivot-ally mounted in bearings 29a and 29b fixed in the supports 2a and 2b, at the centre of the arcuate paths of the tracks 1a and 1b.

The bridging selector member comprises two moving cylindrical contacts 3, of which each one is carried by a flat spring bar 4 which is parallel to the plane of the contact areas of the tracks 1a and 1b. The two blades 4 are connected together by members 30 which are set on the ends of the blades and which pass with a play through sleeves 31 fixed to the moving support 6.

As referred to in connection with the embodiments of Figs. 1 to 5, the connection between each contact 3 and the corresponding blade 4 is insured by a ball 8 housed in a cylindrical cavity 9 of the contact, slightly larger in diameter than the ball and Which carries a collar 10 riveted to the blade 4. On each contact 3 is engaged a clip 11, and the two clips. are connected by a flexible electric conductor 12.

In the selector switch just described, the contact pressure is equally distributed over the two sections of contact on the elementary stud 1b and the corresponding directing track la. The assembly formed by the two contacts 3, thebblades 4 and the members sets itself in its Working position and is disengaged from any rigid connection with the other pieces of the switch.

It is obvious that the invention should not be considered as limited to the forms of execution described and represented, and that modifications can be made thereto Without departing from the scope thereof.

It is to be understood, also, that the invention may be modified to suit the circumstances in which it is to be used.

In particular, it applies to the case when the fixed elementary studs are made of the actual conductor of a winding, as for instance the turns of winding of an 'adjustable potentiometer or those of a variable ratio transformer, the contact areas being rectified or not.

It applies also to the case when the fixed elementary studs be replaced by a continuous surface, for instance a graphitized resistant surface as in adjustable graphitized potentiometers.

I claim:

1. An electrical selector switch comprising a continuous track, a discontinuous track consisting of a plurality of discrete fixed contacts, a selector member mounted for selective movement to connect said continuous track selectively to a discrete fixed contact of said discontinuous track, contact studs on said selector member, said contact studs being mechanically separate from each other, flexible mechanical connection means between said contact studs, flexible electrical connection means between said contact studs to effect only electrical connection therebetween and said contact studs each being mounted on a flexible leaf spring located parallel to the plane of the track, for applying said contact studs under sliding pressure on said tracks.

2. An electrical selector switch comprising a continuous track, a discontinuous track consisting of a plurality of discrete fixed contacts, a selector member mounted for selective movement to connect said continuous track selectively to a discrete fixed contact of said discontinuous track, contact studs on said selector member, said contact studs being mechanically separate from each other, flexible mechanical connection means between said contact studs, flexible electrical connection means between said contact studs to effect only electrical connection therebetween, said contact studs each being mounted on a flexible leaf spring located parallel to the plane of the track, for applying said contact studs under sliding pressure on said tracks and each of said contact studs being rigid and having a plane surface defined by a sharp edge.

3. An electrical selector switch comprising a continuous track, a discontinuous track consisting of a plurality of discrete fixed contacts, a selector member mounted for selective movement to connect said continuous track selectively to a discrete fixed contact of said discontinuous track, contact studs on said selector member, said contact studs being mechanically separate from each other, flexible mechanical connection means between said contact studs, flexible electrical connection means between said contact studs to efiect only electrical connection therebetween, said contact studs each being mounted on a flexible leaf spring located parallel to the plane of the track, for applying said contact studs under sliding pressure on said tracks, each of said contact studs being rigid and having a plane surface defined by a sharp edge and each of said contact studs comprising a cylindrical cavity whose axis is at right angles to said plane surface of said contact stud.

4. An electrical selector switch comprising a continuous track, a discontinuous track consisting of a plurality of discrete fixed contacts, a selector member mounted for selective movement to connect said continuous track selectively to a discrete fixed contact of said discontinuous track, contact studs on said selector member, said contact studs being mechanically separate from each other, flexible mechanical connection means between said contact studs, flexible electrical connection means between said contact studs to eflect only electrical connection therebetween, said contact studs each being mounted on a flexible leaf spring located parallel to the plane of the track, for applying said contact studs under sliding pressure on said tracks and said tracks being located parallel to each other on opposite sides of said selector member.

5. An electrical selector switch comprising a continuous track, a discontinuous track consisting of a plurality of discrete fixed contacts, a selector member mounted for selective movement to connect said continuous track selectively toga discrete fixed contact of said discontinuous track, contact studs on said s'elecfor' member, said Contact studs being mechanically separatefrom each other, flexible mechanical connection means between said contact studs, flexible electrical connection means between said contact studs to eifect only electrical connection therebetween, said contact studs each being mounted on a flexi- :ble leaf spring located parallel to the plane of the track, for applying said contact studs under sliding pressure on said tracks and said tracks being located in the same plane on one side of said selector member.

6. An electrical selector switch comprising a continuous track, a discontinuous track consisting of a plurality of discrete fixed contacts, a selector member mounted for selective movement to connect said continuous track selectively to a discrete fixed contact of said discontinuous track, contact studs on said selector member, said contact studs being mechanically separate from each other, flexible mechanical connection means between said contact studs, flexible electrical connection means between said contact studs to eflect only electrical connection therebetween and a spring blade connected to each of said contact studs, and a strut at the end of each of said spring blades and connecting said blades together.

7. An electrical selector switch comprising a continuous track, a discontinuous track consisting of a plurality of discrete fixed contacts, a selector member mounted for selective movement to connect said continuous track selectively to a discrete fixed contact of said discontinuous track, contact studs on said selector member, said contact studs being mechanically separate from each other, flexible mechanical connection means between said contact studs, flexible electrical connection means between said contact studs to eflEect only electrical connection therebetween, a spring blade connected to each of said contact studs, a strut at the end of each of said spring blades and connecting said blades together and a driving arm between said contact studs, said struts passing freely through said driving arm, and insulation means between said struts and said driving arm.

8. An electrical selector switch comprising a continuous track, a discontinuous track consisting of a plurality of discrete fixed contacts, a selector member mounted for selective movement to connect said continuous track selectively .to a discrete fixed contact of said discontinuous track, contact studs on said selector member, said contact studs being mechanically separate from each other, flexible mechanical connection means between said contact stud-s, flexible electrical, connection means between said contact studs to effect only electrical connection therebetween, and insulated driving arm interconnecting said contact studs, a spring blade connected to each of said contact studs, and rigid plate-like connector members between the ends of said spring blades and said driving arm.

9. An electrical selector switch comprising a continuous track, a discontinuous track consisting of a plurality of discrete fixed contacts, a selector member mounted for selective movement to connect said continuous track selectively to a discrete fixed contact of said discontinuous track, contact studs on said selector member, said contact studs being mechanically separate from each other, flexible mechanical connection means between said contact studs, flexible electrical connection means between said contact studs to effect only electrical connection therebetween, each of said contact studs comprising a cylindrical cavity whose axis is at right angles to said plane surface of said contact stud, a spring blade connected to each of said contact studs, a strut at the end of each of said spring blades and connecting said blades together, and a ball member located freely in said cavity in each of said contact studs, and a stem secured to said ball member and to the associated one of said spring blades.

10. An electrical selector switch comprising a continuous track, a discontinuous track consisting of a plurality of discrete fixed contacts, a selector member mounted for selective movement to connect said continuous track selectively to adiscrete fixed contact of said discontinuous track, contact studs on said selector member, said contact studs being mechanically separate from each other, flexible mechanical connection means between said contact studs, flexible electrical connection means between said contact stud-s to eifect only electrical connect iontherebetween, means applyingsa-id contact studs under sliding pressure on said tracks, each of said contact studs comprising a cylindrical cavity whose axis is at right :angles to said plane surface of said contact stud a spring blade connected to each of said contact studs, a strut at the end of each of said spring blades and connecting said blades together, a ball member located freely in said cavity in each of said contact studs, and a stem secured to said ball member and to the associated one of said spring blades.

11. An electrical selector switch comprising a continuous track, a dis-continuous track consisting of a plurality of discrete fixed contacts, a selector member mounted for selective movement to connect said continuous track selectively to a discrete fixed contact of said discontinuous track, contact studs on said selector member, said contact studs being mechanically separate from each other, flexible mechanical connection means between said contact studs, flexible electrical connection means between said contact studs to effect only electrical connection therebetween, said contact studs each being mounted on a flexible leaf spring located parallel to the plane of the track, for applying said contact studs under sliding pressure on said tracks and said discontinuous track comprising a plurality of mutually imbricated studs.

12. An electrical selector switch comprising a continuous track, a discontinuous track consisting of a plurality of discrete fixed contacts, a selector member mounted for selective movement to connect said continuous track selectively to a discrete fixed contact of said discontinuous track, contact studs on said selector member, said contact studs being mechanically separate from each other, flexible mechanical connection means between said contact studs, flexible electrical connection means between said contact studs to effect only electrical connection therebetween, each of said contact studs comprising a cylindrical cavity whose axis is at right angles to said plane surface of said contact stud, a spring blade connected to each of said contact studs, a strut at the end of each of said spring blades and connecting said blades together, a ball member located freely in said cavity in each of said contact studs, and a stem secured to said ball member and to the associated one of said spring blades and said discontinuous track comprising a plurality of mutually im-bricated studs.

13. An electrical selector switch comprising a continuous track, a discontinuous track consisting of a plurality of discrete fixed contacts, a selector member mounted for selective movement to connect said continuous track selectively to a discrete fixed contact of said discontinuous track, contact studs on said selector member, said contact studs being mechanically separate from each other, flexible mechanical connection means between said contact studs, flexible electrical connection means between said contact studs to eifect only electrical connection therebetween, each of said contact studs being rigid and having a plane surface defined by a sharp edge, each of said contact studs comprising a cylindrical cavity whose axis is at right angles to said plane surface of said contact stud, said tracks being located parallel to each other on opposite sides of said selector member, a spring blade connected to each of said contact studs, a strut at the end of each of said spring blades and connecting said blades together, a driving arm between said contact studs, said struts passing freely through said driving arm, in-

7 sulation means between said struts and said driving arm, a ball member located freely in said cavity in each of said contact studs, a stem secured to said ball member and to the associated one of said spring blades and said discontinuous track comprising a plurality of mutually irnbricated studs.

References Cited in the file of this patent UNITED STATES PATENTS 452,359 Briggs May 19, 1891 8 Wellens Oct. 10, 1904 Temple Feb. 19, 1907 Root Dec. 1, 1908 Procter May 14, 1940 FOREIGN PATENTS Germany Jan. 10, 1916 

